oil rig 
noun
A structure with equipment for drilling an oil well; an oil platform.If we had the latticed structure it would turn the ride into a more industrial looking structure, more like an oil rig....
- As the boys try to escape from the village, they encounter a large tanker truck, which the audience initially believes is an oil rig.
- The Spanish producers of the film, mostly set on an oil rig in the North Sea, had planned to shoot in the republic but their search for a suitable location came up dry.